1. Field of the Invention
The present invention pertains to integrally molded housing for electrical connectors, and in particular to connectors having insulation displacement type terminals mounted therein. More specifically, the present invention pertains to improved strain relief means to prevent the accidental removal of a wire terminated to the connector.
2. Brief Description of the Prior Art
Due to economies of total applied cost, connectors having insulation displacement terminals are becoming increasingly popular. Generally, in these types of connectors a wire is moved laterally of its axis to be received within an insulation displacing terminal. These terminals typically include the pair of opposed insulation severing edges, with a wire-receiving gap therebetween. As the wire is inserted into the gap, the edges sever and displace the insulation, allowing conductive engagement between the terminal edges and the conductor of the insulationclad wire. The terminal is typically associated with an insulated housing having a terminal receiving cavity formed therein, and a wire connecting region adjoining the cavity for receiving a wire moved laterally of its axis into the cavity to be terminated in the terminal. Typically strain relief means are formed on the housing adjacent the wire connecting region to prevent accidental extraction of the wire from the terminal.
One form of strain relief means is disclosed in U.S. Pat. No. 4,178,055, wherein a single resilient finger extends into the wire connecting region to define a constricted wire receiving entrance. The finger is resiliently moveable to allow a wire to pass through the entrance into the cavity for connection to the terminal. To be economically attractive, connector housings must be integrally molded. Those skilled in the molding art will realize that the molding die must include wall-like members extending between the resilient finger and its opposing wall forming the cavity entrance. As connector sizes, and in particular as insulation-clad wire conductor sizes become smaller, the wire-receiving gap defined by the cavity entrance becomes arbitrarily fixed in size. For small wire conductor sizes, this gap may be significantly large compared to the diameter of the insulation-clad wire, and accordingly, effective strain relief may not be provided. Further, the restricted entrance of this particular connector housing is limited in its ability to receive relatively large wire sizes, since only one resilient finger is provided. That is, a wire being inserted through the entrance is allowed passage into the cavity only to the extent allowed by deflection of the sole resilient finger, the opposing entrancedefining member being a rigid extension of the housing wall.
An improvement over the strain relief means described above is provided in a well known connector housing wherein the wirereceiving entrance is defined by a pair of opposed resilient fingers generally converging toward each other to define the constricted wire receiving entrance. In a multicircuit connector, the pair of opposed fingers are arranged in a linear array, side-by-side, in a single row. During reception of a wire in the entrance, both fingers are deflected toward the housing members from which they depend. An improved wire-receiving action is obtained in this housing, since the two resilient fingers are provided to accept a wider range of conductor sizes. However, the thickness of the opposing fingers limit the size of the wire to an amount less than the maximum obtainable, as defined by the dimensions of the terminal receiving cavities (that is, the distance between adjacent walls, extending in the direction of wire length defining the terminal-receiving cavity). Again, wall-like members of the molding die must be provided between each pair of opposed fingers, thereby introducing an arbitrary gap between resilient fingers. As the wire sizes become smaller, this gap becomes significant in size, permitting accidental removal of a terminated wire between the resilient fingers.
Accordingly, it is an object of the present invention to provide effective strain relief means for mass termination insulation displacement type connectors, having integrally molded housings.
Another object of the present invention is to provide improved strain relief means for connector housings of the above described type, in which terminal centerline spacing or progression can remain constant over a range of larger conductor sizes.
It is a further object of the present invention to provide strain relief means of the above-described type wherein wires having diameters corresponding to the lateral distance between adjacent cavity-defining, inter-terminal walls can be simultaneously mass inserted in the connector.